JPH1039719A - Image forming device, process cartridge and developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent low image density which occurs at the beginning of the use of a process cartridge and fog image which occurs after it is used for some time, in an image forming device having two or more processing speeds. SOLUTION: From the number of sheets of prints stored in a storage means 30, the amount of the use of the process cartridge corresponding to the processing speed is judged. In the case the number of sheets of the prints is small, the voltage of a primary bias which is supplied from a high-voltage unit 100 to a charge roller 2 is corrected according to the processing speed. Thus, the surface potential of a photoreceptive drum is changed. Further, by changing the surface potential of the photoreceptive drum gradually according to the amount of the use, variations in print width and line width are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge, a developing device, and an electrophotographic image forming apparatus to which the process cartridge or the developing device can be attached and detached.

Here, as an electrophotographic image forming apparatus, for example, an electrophotographic copying machine, an electrophotographic printer (for example, L
ED printers, laser beam printers, etc.), electrophotographic facsimile machines, and electrophotographic word processors.

A process cartridge is one in which charging means, developing means or cleaning means and an electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is made detachable from an electrophotographic image forming apparatus main body. Alternatively, at least one of a charging unit, a developing unit, and a cleaning unit and an electrophotographic photosensitive member are integrally formed into a cartridge so as to be detachable from an electrophotographic image forming apparatus main body. This means that the body is integrally formed into a cartridge so as to be detachable from the main body of the electrophotographic image forming apparatus.

[0004]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image forming process, an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is used as an image forming apparatus. A process cartridge system detachable from the main body is employed. According to this process cartridge system, the maintenance of the apparatus can be performed by the user himself without relying on a service person, so that the operability can be remarkably improved. Therefore, this process cartridge system
Widely used in image forming apparatuses.

[0005]

By the way, in recent years, the resolution of printers has been increased, and 900 dpi, 1200 dpi
Printers having a high resolution of i have been produced. However, if the resolution is increased from, for example, 600 dpi to 1200 dpi, the number of revolutions of the polygon mirror in the scanner unit must be doubled, and
Since a print speed of 30,000 rpm or more is required for a printer per minute, there arise technical and cost problems. As a countermeasure, for example, in the case of a printer of 600 dpi and 12 sheets / min (process speed of about 70 mm / sec), in the 1200 dpi mode, the process speed is switched to half and 1200 dpi and 6 sheets / min (process speed of about 35 mm / sec). / Sec), printers of the resolution and process speed switching type are operated. With this method, the number of rotations of the polygon mirror can be kept constant irrespective of the resolution, so that there is no technical or cost problem of the scanner unit.

In the above-described apparatus, when image data having different resolutions are successively sent from the host computer, different resolution data is printed in a continuous printing operation in order to perform printing successively.

The present invention is a further development of the prior art.

Accordingly, a first object of the present invention is to provide a print image having a density of a print image and a line width of a character or a figure in a state after the use of the process cartridge or the developing device for a while. An object of the present invention is to provide a process cartridge, a developing device, and an image forming apparatus provided with the process cartridge or the developing device, which realize prevention of fluctuation.

A second object of the present invention is to provide a process cartridge, a developing device, and a process cartridge for accurately detecting the life of an electrophotographic photosensitive member and preventing the occurrence of a fog image before white spots occur. An object of the present invention is to provide an image forming apparatus provided with the developing device.

A third object of the present invention is to provide a process cartridge, a developing device, and an image forming apparatus having the process cartridge or the developing device capable of preventing a fogged image due to an increase in reversal toner. .

[0011]

The above object is achieved by a process cartridge, a developing device, and an image forming apparatus having the process cartridge or the developing device according to the present invention. In summary, the present invention provides an electrophotographic photosensitive member, a process unit acting on the electrophotographic photosensitive member, and information on the process cartridge in a process cartridge detachable from an image forming apparatus main body having two or more process speeds. And a storage means for storing data corresponding to the process speed.

It is preferable that the information stored in the storage means includes at least a usage amount of the process cartridge at each process speed. The image forming apparatus main body includes a high-voltage power supply for supplying power to the process unit, the information stored in the storage unit includes at least a usage amount of the process cartridge at each process speed, and a process cartridge at each process speed. It is preferable to correct the image forming conditions at the time of printing at a certain process speed in accordance with the usage amount of.

The image forming apparatus main body includes a high-voltage power supply for supplying power to the process means, and the information stored in the storage means includes at least a use amount of the process cartridge at each process speed. When the used amount of the process cartridge is less than or equal to the predetermined amount, it is preferable that the correction is made in a direction to promote the image forming condition at the time of printing at a certain process speed.

The image forming apparatus main body includes a high-voltage power supply for supplying electric power to the process means, and the information stored in the storage means includes at least a use amount of the process cartridge at each process speed. When the used amount of the process cartridge in the above is not less than a predetermined amount, it is preferable to send a signal indicating a process cartridge replacement time to the image forming apparatus main body or the computer.

According to another aspect of the present invention, in a process cartridge detachable from an image forming apparatus main body,
An electrophotographic photoreceptor, a process unit that acts on the electrophotographic photoreceptor, and a storage unit that stores information about a process cartridge in accordance with a process speed. A developing bias application unit that applies an oscillating voltage superimposed with an AC voltage, wherein the information stored in the storage unit includes at least the usage amount of the process cartridge, and when the usage amount of the process cartridge is equal to or more than a predetermined amount, The alternating voltage of the oscillating voltage has a predetermined pause time after voltage vibration for a predetermined time, and this is repeated periodically, and a cycle for setting the pause time according to the total usage amount of the process cartridge. The process cartridge is characterized in that the process cartridge is variable and is corrected in a direction to promote the image forming condition. It is subjected.

According to another aspect of the present invention, there is provided an image forming apparatus in which a process cartridge is detachable and which forms an image on a recording medium, comprising: (a) an electrophotographic photosensitive member; Process means acting on
Mounting means for removably mounting a process cartridge having storage means for storing information relating to the process cartridge in accordance with the process speed; and (b) transport means for transporting the recording medium. An image forming apparatus is provided.

Further, according to another aspect of the present invention, there is provided an image forming apparatus for detachably attaching a process cartridge and forming an image on a recording medium, comprising: (a) an electrophotographic photosensitive member; And a storage unit for storing information about the process cartridge in accordance with the process speed. The image forming apparatus main body includes a developing unit included in the process unit and a vibration unit in which an AC voltage is superimposed on a DC voltage. It has a developing bias applying unit for applying a voltage, the information stored in the storage unit includes at least the usage amount of the process cartridge,
When the usage amount of the process cartridge is equal to or more than a predetermined amount, the AC voltage of the oscillating voltage has a predetermined pause time after voltage vibration for a predetermined time, which is periodically repeated, and the total use of the process cartridge is performed. Mounting means for removably mounting, in the apparatus main body, a process cartridge for making the cycle for setting the pause time variable according to the amount and correcting the image forming conditions in a direction to promote image forming conditions; and (b) the recording medium And a transport unit for transporting the image.

According to another aspect of the present invention, in a developing device having a developing means provided with a developing container and detachable from an image forming apparatus main body, information on the developing device is stored in correspondence with a process speed. There is provided a developing device characterized by having a storage means for performing the operation.

Further, according to another aspect of the present invention, in a developing device having a developing means provided with a developing container and detachable from the main body of the image forming apparatus, information on the developing device is stored corresponding to the process speed. The image forming apparatus main body includes a developing bias applying unit that applies an oscillating voltage obtained by superimposing an AC voltage on a DC voltage to the developing unit, and the information stored in the storing unit includes at least a developing unit. Including the amount of use of the device, when the amount of use of the developing device is equal to or more than a predetermined amount, the AC voltage of the oscillating voltage has a predetermined pause time after voltage vibration for a predetermined time, and this is periodically repeated. In addition, the present invention provides a developing device characterized in that a cycle for setting a pause time is made variable in accordance with the total usage amount of the developing device, and correction is made in a direction to promote image forming conditions.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus, a process cartridge and a developing device according to the present invention will be described in more detail with reference to the drawings.

Embodiment 1 First, an embodiment of an image forming apparatus to which a process cartridge constructed according to the present invention can be mounted will be described with reference to FIGS.

FIG. 1 schematically shows an electrophotographic image forming apparatus using a process cartridge (hereinafter, referred to as a cartridge) for forming an image using reversal development. The image forming apparatus used in this embodiment has a resolution of 1
200 dpi, process speed 35 mm / sec,
Resolution 600 dpi, process speed 70mm / se
It is assumed that the second speed control of c is performed.

In this embodiment, as shown in FIG. 2, the cartridge 20 includes a photosensitive drum 1, which is an electrophotographic photosensitive member.
A photosensitive drum unit 12 integrating a charging roller 2 as a charging unit and a cleaner unit 10 as a cleaning unit including a cleaning blade 11;
Are integrated by the frame bodies 60 and 70, and can be exchanged with the apparatus main body 18 via the mounting guide means 80 as shown in FIG.

A transfer roller 9 serving as a transfer charging means is disposed on the apparatus main body 18 below the photosensitive drum 1 in the cartridge 20. Further, with respect to the transfer roller 9, a paper feed roller 15 is disposed on the paper feed side, while a fixing roller 13 for fixing the toner 5 transferred to the recording paper is provided on the paper discharge side.
A pressure roller 14, which presses the recording paper against the fixing roller 13 to assist in fixing, and a paper discharge roller 16, which constitutes a part of the conveying means for discharging the recording paper on which the toner is fixed, to the outside of the apparatus main body 18 as shown by an arrow, are arranged. Have been.

Further, above the cartridge 20, an exposure device 3 for irradiating the photosensitive drum 1 charged by the charging roller 2 with a laser beam to form an electrostatic latent image on a photosensitive surface is arranged.

The developing device 4 includes a developing container 4a for accommodating the toner 5, a developing roller 7 rotatably provided at an opening of the developing container 4a, and a sheet metal 6 fixed to the developing container 5a.
a developing blade 6 that is adhered and fixed to a and regulates the toner layer thickness on the developing roller 7; and a stirring rod 8 that stirs the toner moved to the developing blade 7 side.

A high-voltage unit 100 for applying a bias to the developing roller 7 and the charging roller 2 is provided in the apparatus main body 18. Between the developing roller 7 and the high-voltage unit 100, a developing roller electrode 51 receiving a developing bias, Further, a developing bias electrode 102 that connects the developing roller electrode 51 to the high voltage unit 100 and applies a developing bias to the developing roller electrode 51 is provided.

The charging roller electrode 5 receives a primary bias applied to the charging roller 2 from the high voltage unit 100.
2, and a primary bias electrode 109 that connects the charging roller electrode 52 to the high-voltage unit 100 and applies a primary bias to the charging roller electrode 52.

Furthermore, a drum ground electrode 50 for grounding the photosensitive drum 1 and a main body side ground electrode 101 connected to the drum ground electrode 50 and connected to a conductive metal frame (not shown) are provided.

In the present embodiment, a storage means 30 using a non-volatile memory (NVRAM) is attached to the lower part of the developing device 4 in the present embodiment, and the connector 200 is connected to a CPU 181 disposed in the apparatus main body 18. Connected through.

Hereinafter, an image forming process of the image forming apparatus will be described.

The photosensitive drum 1 rotates in one direction about its axis. The photosensitive drum 1 includes a high-voltage unit 10
After the surface is uniformly charged by a primary bias superimposed on an AC component and a DC component supplied from 0 to the charging roller 2, an electrostatic latent image is formed by a laser beam emitted from the exposure device 3. The developing roller 7 receives replenishment of the toner 5 from the inside of the developing container 4a and applies the toner 5 uniformly coated on the surface by the developing blade 6 to the high-pressure unit 100.
With the developing bias from, the toner is attached to the electrostatic latent image on the photosensitive drum 1 and visualized.

On the other hand, the paper feed roller 14 feeds a paper 17 as a recording medium between the photosensitive drum 1 and the transfer roller 9 from outside the image forming apparatus 18. The image of the photosensitive drum 1 visualized by the toner 5 is transferred onto the paper 17 by the transfer roller 9. The toner 5 transferred onto the paper 17 is
Is fixed by the heat generated by the pressure and the pressure applied by the pressure roller 14 to form a recorded image.

Thereafter, the paper 17 is discharged to the outside of the image forming apparatus 18 by the discharge roller 16. After the residual toner on the photosensitive drum 1 remaining without being transferred is removed by the cleaning blade 11 attached to the cleaning unit 10, the photosensitive drum 1 is uniformly charged again by the charging roller 2, and thereafter, the above-described steps are performed. repeat.

The storage means 30 includes a CPU 1
The total number of prints of the resolution of 600 dpi and the process speed of 70 mm / sec and the resolution of 1200 dpi and the process speed of 35 mm / sec input from 81 are stored, and the number of prints is added each time one print is performed. .

The information to be stored in the storage means 30 is not particularly limited as long as the amount of use of the cartridge 20 can be determined by the image forming apparatus 18. For example, the information includes the total application time of the primary charging of the photosensitive drum 1, the total driving time of the photosensitive drum 1, and information on the total number of rotations.

When the cartridge 20 is mounted on the image forming apparatus 18, the storage means 30 is connected to the CPU 181. The number of prints is sequentially written or read into the storage means 30 by the CPU 181.

In this embodiment, when it is determined that the cartridge 20 has not been used for a long time based on the number of prints stored in the storage means 30, the high-voltage unit 100
Is characterized in that the primary bias voltage supplied to the charging roller 2 is reduced.

The reason for lowering the primary bias voltage will be described below.

The potential when the surface of the photosensitive drum 1 is charged by the primary bias is denoted by Vd, and the potential lowered by exposure is denoted by Vl. The developing bias applied to the developing roller 7 is set to Vdc. The developing bias Vdc is set lower than Vd and higher than Vl. Further, the potential difference between Vl and the developing bias Vdc is determined by the contrast potential Vcnt.
And

Here, if Vd is made lower than usual, Vl
Also decrease accordingly. Image forming apparatus 18 of the present embodiment
The relationship between Vd and Vl in the photosensitive drum 1 used in FIG. As shown in the graph of FIG.
Is -150V, Vl is -150V. On the other hand, when Vd is lowered to -550 V, V
l is as low as -100V.

In the reversal development performed by the image forming apparatus 18 of the present embodiment, the contrast potential Vcnt, which is the potential difference between the developing roller 7 and the photosensitive drum 1, is used to develop the electrostatic latent image with the toner 5 by using the contrast. As the value of the potential Vcnt increases, the toner 5 adheres to the Vl portion. Therefore, in the initial state of the cartridge 20 in which the toner 5 has a low triboelectricity and a low developing property, the developing bias V
By keeping dc constant, lowering Vd and optimizing Vl, developability equal to that of a state other than the initial state with a high tribo can be achieved.

In the case of the image forming apparatus 18 of this embodiment, Vd
Is -650V, Vl is -150V, the developing bias Vdc is -500V, and the contrast potential Vcnt is 350V.
i, in the case of printing only at a process speed of 70 mm / sec, the change in the line width of the printed image from the start of printing until printing of 500 sheets was as shown in the graph of FIG.
From this graph, it can be seen that in the image forming apparatus 18 of the present embodiment, a sufficient print line width can be obtained when printing about 150 sheets, and the image is not in the initial state.

Similarly, in the case of printing at a resolution of 1200 dpi and a process speed of 35 mm / sec, the line width of the printed image from the start of printing to the printing of 500 sheets was as shown in the graph of FIG. From this graph, it can be seen that a sufficient printing line width can be obtained when printing about 300 sheets, and the printing is not in the initial state. Sufficient print line widths and print density sheets naturally vary depending on the setting conditions of the image forming apparatus and the process cartridge.

4 and 5, the fluctuation of the print line width is not constant. In the case of FIG. 4, the print line width changes almost from the initial 50th sheet, and in the case of FIG. After that, it has changed almost linearly thereafter. Therefore, a resolution of 600 dpi and a process speed of 70 mm
/ Sec, the resolution is 120
In the case of 0 dpi and the process speed is 35 mm / sec,
From the initial to the 100th sheet, Vd is -550V,
l was -100 V, and the contrast potential Vcnt was 400 V.

In the case of a resolution of 600 dpi and a process speed of 70 mm / sec, the 50th to 150th sheets have a resolution of 1200 V with a voltage of 10 V every 10 sheets.
When the process speed is 35 mm / sec, Vd is increased by 10 V every 20 sheets from the 100th sheet to the 300th sheet to prevent the line width from becoming too thick. Then, the line width at that time changed as shown in the graphs of FIGS. 6 and 7, and the line width from the beginning of use could be optimized. Also, there was no light concentration in the initial stage of use.

Similarly, in the case of mixed printing of a resolution of 600 dpi and a process speed of 70 mm / sec and a resolution of 1200 dpi and a process speed of 35 mm / sec, the number of prints at a process speed of 70 mm / sec is x, a resolution of 1200 dpi and a process speed of 35 mm.
/ Sec, y ≦ 0 × 2x + y <100
In this case, Vd was -550 V, Vl was -100 V, and the contrast potential Vcnt was -400 V.

When 100 ≦ 2x + y <120,
When Vd = −550V, 120 ≦ 2x + y <140,
When Vd = −560 V, 140 ≦ 2x + y <160,
When Vd = −570V and 160 ≦ 2x + y <180,
Vd = −580V, 180 ≦ 2x + y <200,
When Vd = −590 V and 200 ≦ 2x + y <220,
When Vd = −600 V, 220 ≦ 2x + y <240,
Vd = −610V, 240 ≦ 2x + y <260,
Vd = −620V, 260 ≦ 2x + y <280,
Vd = −630V, 280 ≦ 2x + y <300,
When Vd = -640V and 300≤2x + y, Vd =-
650 V and Vd were increased by 10 V each to prevent the line width from becoming too large. At this time, Vl
Is constant at -100V, and the contrast potential Vcnt is constant at -400V. Also at this time, the line width from the early stage of use could be optimized, and the density was not low in the early stage of use.

As described above, in the present embodiment, the number of prints stored in the storage means 30 of the cartridge 20 is 600 pi at a resolution of 70 mm / process speed.
In the case of sec, Vd is -550V within 50 sheets,
The high voltage unit was controlled so that Vd was increased by 10 V every 10 sheets up to 150 sheets. Specifically, in this embodiment, the number of printed sheets is between 50 and 150,
The voltage output by the high voltage unit 100 was controlled based on the following equation.

Formula A ′) Output voltage = −650 + ｛100
− | (Number of prints−50 / 10) | × 10} Also, resolution 1200 dpi, process speed 35 m
In the case of m / sec, Vd is -550V within 100 sheets.
The high voltage unit was controlled so that Vd was increased by 10 V every 20 sheets up to the 300th sheet. Specifically, in this embodiment, the number of printed sheets is 100 to 30.
The voltage output from the high-voltage unit 100 was controlled based on the following equation during the zero sheet.

Equation A ″) Output voltage = −650 + ｛100
− | (Number of prints−100 / 20) | × 10} In the case of mixed printing (x is the number of prints at a resolution of 600 dpi and a process speed of 70 mm / sec, x is a resolution of 120)
The number of prints at 0 dpi and a process speed of 35 mm / sec is defined as y. ) For 2x + y <100, Vd is -55.
0V, 2x + y is 2 when 100 ≦ 2x + y <300
The high voltage unit was controlled so that Vd was increased by 10 V each time it increased by 0. Specifically, in this embodiment, when 100 ≦ 2x + y <300, the high-pressure unit 1
The voltage output by 00 was controlled based on the following equation.

Formula A) Output voltage = −650 + [100−
| {(2x + y) −100/20} × 10] The control of the image forming apparatus 18 according to the present embodiment will be described with reference to FIGS. First, FIG. 8 shows a block diagram of the present embodiment.

In FIG. 8, the cartridge 20 has a storage means 30 for storing the number of prints, and the image forming apparatus 18 has a read / write means 182 for reading and writing information from and to the storage means 30, and a storage means. 3
The determination means 183 for determining the usage amount of the cartridge 20 based on the information read from 0, the high-pressure unit 100, C
When the PU 181 is provided, and the judging means 183 judges from the number of prints at each process speed stored in the cartridge 20 that the cartridge 20 has just started to be used, it sends a signal to the CPU 181. send.

When receiving the signal from the judging means 183, the CPU 181 controls so as to lower the voltage of the primary bias output from the high voltage unit 100. At this time,
The CPU 181 performs an operation in accordance with Expression A, and uses the result as an output of the high-voltage unit 100.

After printing is completed, the number of printed sheets corresponding to each process speed is added to the number of printed sheets at each process speed read from the storage means 30 and input to the storage means 30 via the read / write means 182. Remember.

Next, control of the image forming apparatus of this embodiment will be described with reference to the flowchart of FIG.

First, when an image signal is input from an image signal input unit such as a computer, the CPU 181 reads information on the number of prints from the storage unit 30 through the read / write unit 182 (step 1). Next, the determination unit 183 determines that the number of prints at a resolution of 600 dpi and a process speed of 70 mm / sec is x and the resolution is 1200d.
pi, assuming that the number of prints at a process speed of 35 mm / sec is y, it is determined whether 2x + y <100 (step 2). If the number of printed sheets is not 100 <2x + y, it is determined whether 100 ≦ 2x + y <300 (step 3). Here, if 300 ≦ 2x + y, a sufficient print line width and print density can be obtained.
The printing is performed without changing the setting (step 4).

Then, the number of printed sheets at this time is added to the number of printed sheets read from the storage means 30 (step 5), and written in the storage means 30 through the read / write means 182 (step 6), and the printing operation is completed. (Step 7).

In step 2, if 2x + y <100, the CPU 181 sets the output voltage (primary bias) of the high voltage unit 100 to -550 V (step 8), proceeds to step 4, and thereafter executes the same process as described above. .

In step 3, if the number of prints is 1
If 00 ≦ 2x + y <300, the output voltage (primary bias) of the high-voltage unit 100 is set to the result calculated based on Expression C (Step 9), and the process proceeds to Step 4;
Perform the same process as above.

As described above, according to the present embodiment,
By changing the surface potential of the photosensitive drum according to the usage amount of the process cartridge, it was possible to prevent variations in print density and print line width. Further, by changing the surface potential stepwise, it was possible to prevent the line width from becoming too large.

In this embodiment, since the means for storing information on the used amount is provided in the process cartridge, even if another process cartridge is temporarily used during use, the process to be used is The line width and print density can be adjusted according to the cartridge.

In this embodiment, the case where reversal development is performed has been described. However, in an image forming apparatus that performs regular development, a similar effect can be obtained by increasing the surface potential when the process cartridge is in the initial state. Obtainable.

Embodiment 2 As shown in FIG. 10, a developing device 20A of this embodiment includes a developer carrier 7 such as a developing roller and a developer (toner) for supplying the developer carrier 7 to the developer carrier. The developing container 4 a containing the toner 5 therein is provided with a plastic frame 7.
0 makes the cartridge integral. That is, the developing device 20 </ b> A of the present embodiment can be considered as a cartridge integrated with the process cartridge 20 described in the first embodiment except for the photosensitive drum 1, the charging roller 2, and the cleaning unit 10.

Therefore, the description of the structure and operation of the developing device 20A provided with the storage means 30 is the same as in the first embodiment.

Third Embodiment A third embodiment according to the present invention will be described with reference to FIGS.

The present embodiment is characterized in that by changing the developing bias applied to the developing means, fluctuations in the print line width and print density immediately after the use of the process cartridge is prevented.

The developability of the image forming apparatus 18 is adjusted by the magnitude of the contrast potential Vcnt as described in the first embodiment. Therefore, when the potential Vl at the time of exposure on the surface of the photosensitive drum is kept constant, a constant developing property can be maintained by changing the developing bias Vdc according to the usage amount of the cartridge 20 at each process speed. .

In this embodiment, Vd is -650 V and Vl is-
If the number of prints stored in the storage means of the cartridge is 2x + y <100, as in the first embodiment, the developing bias Vdc is set to -550V, and the contrast potential Vcnt is set to -400V. Also, 1
If 00 ≦ 2x + y <300, the developing bias Vdc is set to 2
Each time x + y was increased by 20, the voltage was lowered by 5V.

Here, as in the first embodiment, the number of prints at a resolution of 600 dpi and a process speed of 70 mm / sec is x, and the number of prints at a resolution of 1200 dpi and a process speed of 35 mm / sec is y.

As a result, the print line width from the beginning of use of the cartridge 20 can be optimized. Also, there was no light concentration in the initial stage of use.

FIG. 11 shows a block diagram of the present embodiment. FIG.
1, the cartridge 20 includes a unit 30 for storing the number of prints, and the image forming apparatus 18 includes a read / write unit 182 for reading and writing information from and to the storage unit 30 in substantially the same manner as in the first embodiment. A determination unit 183 for determining the usage amount of the cartridge 20 based on the information read from the storage unit 30;
The CPU 181a includes a CPU 181a. When it is determined from the number of prints at each process speed stored in the cartridge 20 that the cartridge 20 has just started to be used, the CPU 181a determines whether the high-pressure unit 100 Control is performed so as to increase the output voltage of the developing bias.

When 2x + y <1000, the developing bias Vdc is set to −550 V, and 100 ≦ 2x + y <300.
In this case, the developing bias Vdc is output based on the following equation.

Formula B) Output voltage = −500− [50− |
{(2x + y) -100} / 20 | × 5] After the printing is completed, the number of printed sheets is added to the number of printed sheets read from the storage unit 30 and input to the storage unit 30 through the read / write unit 182 and stored. Let it.

Next, the control of the image forming apparatus 18 of this embodiment will be described with reference to the flowchart of FIG.

First, when an image signal is input from an image signal input means such as a computer, the CPU 181a reads information on the number of prints from the storage means 30 through the read / write means 182 (step 11). next,
The determination means 183 determines whether 2x + y <100 (step 12). If 100 ≦ 2x + y, 10
It is determined whether 0 ≦ 2x + y <300 (Step 1)
3). Here, if 300 ≦ 2x + y, a sufficient print line width and print density can be obtained.
(Step 14). Then, at this time, the number of prints at each process speed is added to the number of prints at each process speed read from the storage means 30 (step 15), and written to the storage means 30 by the read / write means 182 (step 15). 16), the printing operation ends (step 17).

In step 12, 2x + y <100
If so, the CPU 181 sets the output voltage (developing bias) of the high-voltage unit 100 to -550 V, and
To carry out the same process as above.

In step 13, 100 ≦ 2
If x + y <300, the output voltage (developing bias) of the high-voltage unit 100 is set to the result calculated based on the formula B, and the process proceeds to step 14, where the same process as described above is performed.

As described above, according to the present embodiment,
By changing the developing bias in accordance with the usage amount of the process cartridge, it was possible to prevent variations in the print line width and print density. Further, by changing the developing bias stepwise, it was possible to prevent the line width from becoming too large.

Embodiment 4 Next, Embodiment 4 according to the present invention will be described with reference to FIGS.
This will be described with reference to FIG.

In the present embodiment, when reversal development is performed, the potential Vl during exposure of the surface of the photosensitive drum is changed by changing the exposure amount of the exposure device, and the contrast potential V
It is characterized by adjusting cnt.

The exposure amounts E and Vl of the image forming apparatus of this embodiment
Is shown in the graph of FIG. According to the graph of FIG. 13, in the image forming apparatus of this embodiment, Vl is set to −15.
In order to make it 0 V, the exposure amount E is set to 0.7 μJ / cm ² . When the process cartridge is in the initial state, the required contrast potential Vcnt is -400 V from the first and third embodiments, and when the developing bias Vdc is kept constant, Vl at that time is -100 V. Therefore, FIG.
According to the graph of FIG. 3, if 2x + y <100, the exposure E is set to 0.9 μJ / cm ² , and if 100 ≦ 2x + y <300, the exposure E is set to 0.02 for every 20 increments of 2x + y.
μJ / cm ^{2 was} changed.

Here, similarly to the first embodiment, the resolution 600
x, number of prints at a process speed of 70 mm / sec x, resolution 1200 dpi, process speed 35 m
The number of prints at m / sec is defined as y.

As a result, the line width of the cartridge 20 from the beginning of use can be optimized. Also, there was no light concentration in the initial stage of use.

FIG. 14 is a block diagram of the present embodiment. 14, the cartridge 20 includes a storage unit 30 for storing the number of prints at each process speed, substantially in the same manner as in the first and third embodiments.
8 is a read / write means 182 for reading and writing information from and to the storage means 30;
Determining means 183 for determining the usage amount of the cartridge 20 based on the information read from the
U181b, the judging means 183 determines from the number of prints at each process speed stored in the cartridge 20 that the CPU 181b
Controls the amount of laser light output from the exposure device 3 to be high.

At this time, the exposure amount E when 100 ≦ 2x + y <300 is output based on the following equation.

Formula C) Exposure amount = 0.7 + [0.2− |
{(2x + y) -100} /20|×0.02] The CPU 181b uses the calculation result of Expression C as the laser light amount of the exposure apparatus 3.

After the printing is completed, the number of printed sheets is added to the number of printed sheets read from the storage means 30, and the read /
The data is input to the storage means 30 through the writing means 182 and stored.

Next, the control of the image forming apparatus 18 of this embodiment will be described with reference to the flowchart of FIG.

First, when an image signal is input from an image signal input means such as a computer, the CPU 181b reads out information on the number of prints from the storage means 30 through the read / write means 182 (step 21). next,
The determination means 183 determines whether 2x + y <100 (step 22). If 100 ≦ 2x + y, 10
It is determined whether 0 ≦ 2x + y <300 (step 2
3). If 300 ≦ 2x + y, a sufficient print line width and print density can be obtained, so that printing is performed without changing the settings of the exposure device 3 (step 24).

Then, the number of printed sheets at each process speed read from the storage means 30 is added to the number of printed sheets at each process speed read from the storage means 30 (step 25). Then, the data is written in the storage means 30 by the read / write means 182 (step 26), and the printing operation is completed (step 27).

In step 22, 2x + y <100
If so, the CPU 181b sets the laser output of the exposure device 3 to 0.9 μJ / cm ² (step 28), proceeds to step 24, and performs the same process as described above.

In step 23, 100 ≦ 2
If x + y <300, the laser output of the exposure apparatus 3 is set to the result calculated based on Expression C (step 29),
Proceed to step 24 to perform the same process as described above.

As described above, according to the present embodiment,
By changing the exposure amount according to the usage amount of the process cartridge, it was possible to prevent fluctuations in the print line width and print density. Further, by changing the exposure amount stepwise, it was possible to prevent the line width from becoming too large.

Fifth Embodiment Next, a fifth embodiment according to the present invention will be described with reference to the flowchart of FIG.

The present embodiment is characterized in that the number of rotations of the photosensitive drum at each process speed is detected to prevent generation of a fog image due to drum scraping.

In the image forming apparatus 18, the photosensitive layer of the drum
When the thickness is 0 μm and becomes 15 μm or less, a fog image occurs. Also, the resolution is 600 dpi and the process speed is 70
In the case of mm / sec, when printing 1,000 sheets, the photosensitive layer of the drum is shaved by 1 μm. Therefore, the life of the scraping of the photosensitive drum is 15,000 sheets. The diameter of the drum is 30mm,
Since the printing time for one sheet is 15 seconds, the resolution is 60
The drum rotation speed at the time of printing one sheet at 0 dpi and a process speed of 70 mm / sec is obtained as follows.

70 mm / sec (process speed) ×
15 sec (printing time for one sheet) = 1050 mm (drum rotation distance for printing) 30π (drum circumference) × a (number of drum rotations for printing one sheet) = 1050 mm (drum rotation distance for printing one sheet) (Resolution 600 dpi, process speed 7
Number of rotations of drum at the time of printing one sheet of 0 mm / sec) = 1
1.14 [rotation speed / sheet] Accordingly, the life rotation speed of the photosensitive drum scraping is 11.14 × 15000 = 167100 (drum life rotation speed).

Similarly, the printing time per sheet is 20 seconds, the resolution is 1200 dpi, and the process speed is 35 mm / sec.
35 mm / sec (process speed) x 20 sec
(Printing time of one sheet) = 700 mm (drum rotation distance at the time of printing one sheet) 30π (drum circumference) × b (number of rotations of the drum at the time of printing one sheet) = 700 mm (drum rotation distance at the time of one printing) (Drum rotation speed when printing one sheet at a resolution of 1200 dpi and a process speed of 35 mm / sec) =
7.43 [rotation speed / sheet].

However, the printing time for one sheet at a resolution of 1200 dpi and a process speed of 35 mm / sec (20
Second) has a resolution of 600 dpi and a process speed of 70 mm
The reason why the time is not twice as long as the one-sheet printing time (15 seconds) of / sec is that the rise time of the fixing device is required regardless of the process speed.

First, it is determined whether or not printing has started (step 31), and the storage means 3 built in the cartridge is determined.
0, resolution 600 dpi, process speed 70 m
m / sec total number of drum rotations (= a x number of prints)
And resolution 1200dpi, process speed 35mm /
The total drum rotation number data, which is the sum of the total drum rotation number (= b × the number of prints) in sec, is read into the CPU (step 2). Here, the total number of rotations of the drum means a resolution of 600 dpi (process speed of 70 mm / sec).
Drum rotation speed 11.14x and resolution 1200dp
i (process speed 35 mm / sec) is obtained by adding the total number of drum rotations 7.43y. Where x is a resolution of 600 dpi and a process speed of 70 mm / sec.
And y is the number of prints when the resolution is 1200 dpi and the process speed is 35 mm / sec.

Next, a comparison is made between the total drum rotational speed data and the drum life rotational speed (167,100 rotational speeds in this embodiment) (step 33). If the total drum rotational speed data is smaller than the drum life rotational speed data, The printing operation starts (step 34). On the other hand, if it is larger, the life of the cartridge is notified to the external device (step 44), and the process ends. That is, the drum life rotation number is written in advance in the storage means 30 of the cartridge, and the value is compared with the total drum rotation number to detect the drum life.

Next, when the printing operation starts (step 3)
4) After the motors are driven (step 35) and the counter is started (step 36), a high voltage obtained by superimposing an AC bias on a DC bias is applied to the charging roller (step 37), and a printing operation is performed. The counter counts the number of prints.

Next, it is determined whether or not the printing operation is completed (step 38). If the printing operation is to be continued, the process returns to step 34 to continue the printing operation and accumulate and count the number of rotations of the drum.

Conversely, when printing is completed, the high voltage applied to the charging roller is turned off (step 39), the counter is stopped (step 40), and each motor is stopped (step 41).

The resolution counted above is 600 dpi.
(Process speed 70 mm / sec) total drum rotation speed and resolution 1200 dpi (Process speed 35 m
m / sec) is written in the storage means 30 (step 42).
At the same time, the CPU compares the accumulated drum rotational speed data with the drum life rotational speed data (step 43). If the accumulated drum rotational speed data is not larger than the drum life rotational speed, the process returns to step 31. If the accumulated drum rotational speed data is larger than the drum life rotational speed, the CPU notifies the life of the cartridge (step 44) to an external device and ends the processing.

The toner amount of the cartridge used in this embodiment is assumed to be 25,000 sheets for A4 and 4% printing. Table 1 below shows fog results when printing up to 25,000 sheets only at a resolution of 600 dpi (process speed of 70 mm / sec). At this time, if the printing is continued without outputting a message for replacing the cartridge to the external device even when the number of prints of the drum life has exceeded, a fog image is generated.

[0108]

[Table 1]

Table 2 below shows the fog results when printing up to 25,000 sheets only at a resolution of 1200 dpi (process speed of 35 mm / sec). The number of drum life prints at this time is 22,500. In the results of Table 2, similarly to the results of Table 1, if printing is continued without outputting a cartridge replacement message to an external device even when the number of prints exceeds the drum life print number, a fog image occurs.

[0110]

[Table 2]

As described above, the drum life can be detected by detecting the drum rotation speed data at the time of applying a bias to the charging roller during printing in the cartridge having the charging roller, so that the life of the drum can be detected. Can be output to equipment. Accordingly, it is possible to prevent the occurrence of a fog image before the occurrence of a blank image, which occurs when intermittent printing is continued at a low printing rate. Here, the life rotation number previously written in the cartridge needs to be larger than the total rotation number when the bias is applied to the charging roller when the intermittent printing is performed with the guaranteed print number of the cartridge.

It is needless to say that the film thickness applied to the drum at this time needs to be such that a fog image is not output even if the drum is scraped at the total number of revolutions.

Embodiment 6 Next, Embodiment 6 according to the present invention will be described with reference to the flowchart in FIG.

The present embodiment is characterized in that the amount of use of the process cartridge at each process speed is detected to prevent printing without toner.

In the image forming apparatus 18, when the toner filling amount of the cartridge is 6500 g and 600 g or more of the toner is consumed, a low density image is generated.

Resolution 600 dpi, process speed 7
In the case of 0 mm / sec, the toner consumption per sheet in A4 and 4% printing is 0.1 g. That is, A4, 100
Toner consumption per printed solid black image is 2.5
g.

Therefore, the toner consumption amount T1 when printing n sheets is:

[0118]

(Equation 1) Becomes Here, Ak is the printing ratio [%].

Similarly, when the resolution is 1200 dpi and the process speed is 35 mm / sec, A4
The toner consumption per sheet is 0.09 g. That is,
The toner consumption per sheet of A4, 100% printed solid black image is 2.25 g.

Therefore, the toner consumption amount T2 when printing n sheets is:

[0121]

(Equation 2) Becomes

However, Bk is the printing ratio [%]. In addition, the resolution is 600 dpi, and the process speed is 70 mm /
In the case of A4, A4, 4% printing, the toner consumption is 0.1 g per sheet, the resolution is 1200 dpi, and the process speed is 35 mm / sec, in the case of A4, 4% printing, the toner consumption is more than 0.09 g per sheet. This is because fogging on the drum occurs in which the inverted toner or the like flies on the drum even when the drum rotates during non-printing. The higher the process speed, the higher the number of rotations of the drum. , Process speed 70m
In the case of m / sec, the amount of toner consumption per sheet is 1200 dpi, process speed 35 mm / sec.
Is larger than the toner consumption per sheet.

In FIG. 17, first, it is determined whether or not printing has been started (step 51). The storage means 30 built in the cartridge reads the resolution of 600 dpi (process speed of 70 mm / sec) and the resolution of 1200 dpi.
The total print number data at (process speed 35 mm / sec) is read into the CPU (step 52).

Then, a resolution of 600 dpi (process speed 70 mm / sec) and a resolution of 1200 dpi
(Total toner consumption at a process speed of 35 mm / sec) is a toner consumption within a range in which no fog image is generated (in this embodiment, the toner consumption in which no fog image is generated is 600 g). A comparison is made (step 53), and the sum of the total amount of toner consumed at each of the resolution of 600 dpi (process speed of 70 mm / sec) and the resolution of 1200 dpi (process speed of 35 mm / sec) is smaller than the toner consumption within a range where no fog image occurs. In this case, the printing operation starts (step 54).

On the other hand, if it is larger, a notification of toner absence of the cartridge is sent to the external device (step 64), and the process is terminated. That is, the toner consumption in a range where no fog image occurs is written in advance in the storage means 30 of the cartridge, and the resolution is 600 dpi (process speed 70 mm / sec) and the resolution 1200 d
The total amount of toner consumed at pi (process speed 35 mm / sec) is compared with the total amount of toner consumed to detect the remaining amount of toner.

After the above printing operation (step 5)
4) Each motor is driven (step 55), and after the counter starts (step 56), a high voltage in which an AC bias is superimposed on a DC bias is applied to the charging roller (step 57), and a printing operation is performed. At this time, the amount of toner consumed at the resolution of 600 dpi (process speed of 70 mm / sec) and the resolution of 1200 dpi (process speed of 35 mm / sec) are counted from the printing ratio.

Next, it is determined whether or not the printing operation has been completed (step 58). If the printing operation is to be continued, the process returns to step 54 to continue the printing operation, and the resolution is 600 dpi (process speed 70 mm / sec) and the resolution 1200d.
The amount of toner consumed at pi (process speed 35 mm / sec) is accumulated and counted.

Conversely, when printing is completed, the high voltage applied to the charging roller is turned off (step 59), the counter is stopped (step 60), and each motor is stopped (step 61).

The resolution 600 dpi counted above
(Process speed 70 mm / sec) and resolution 120
The amount of toner consumed at 0 dpi (process speed 35 mm / sec) is accumulated and written in the storage means 30 (step 62), and the accumulated toner consumption data and the toner consumption in a range where no fog image is generated in advance are calculated as CP.
U compares (step 63). If the accumulated toner consumption data is not larger than the toner consumption in a range where no fogged image is generated in advance, the flow returns to step 51, and if it is larger, the CPU notifies the external device of the toner absence of the cartridge (step 64) and terminates. Becomes

The number of guaranteed cartridge prints used in this embodiment is 600 dpi (process speed 70 dpi).
mm / sec), A4, 6000 sheets with 4% printing,
Resolution 1200 dpi (process speed 35mm / s
In the case of ec), A4, 4% printing is 6666 sheets.

Table 3 below shows 0 sheets, 6000 sheets when A4 and 4% printing are performed up to 12,000 sheets at a resolution of 600 dpi (process speed 70 mm / sec).
This is the result of the solid black density when solid black printing is performed on 12,000 sheets. As can be seen from the results in Table 3, if printing is continued without outputting a cartridge replacement message to an external device even when the toner is out, a low image density occurs.

[0132]

[Table 3]

Table 4 below shows a resolution of 1200 dpi.
(Process speed 35mm / sec), A4, 4%
0, 650 when printing up to 12,000 sheets
This is a result of solid black density when solid black is printed on 0 sheets and 12000 sheets. The results in Table 4 are also similar to the results in Table 3,
If printing is continued without outputting a cartridge replacement message to an external device even when the toner is out, a low image density occurs.

[0134]

[Table 4]

As described above, the remaining amount can be detected during printing in the cartridge having the charging roller, and the cartridge replacement message can be output to the external device. Thus, it is possible to prevent the occurrence of a low density image due to the absence of toner. Here, the amount of toner consumption in a range where no fog image is generated in advance needs to be larger than the amount of toner consumed at each process speed when intermittent printing is performed with the guaranteed print number of the cartridge.

Seventh Embodiment Next, a seventh embodiment according to the present invention will be described with reference to FIGS.
9 will be described.

The resolution used in this embodiment is 600 dp.
i, In an image forming apparatus having a process speed of 70 mm / sec, the guaranteed number of prints of the cartridge is 6000 for A4 and 4% printing.

FIG. 19 shows the waveform of the developing bias.
(A) shows a conventional developing bias waveform, and (b) and (c) show a developing bias waveform according to the present embodiment. (A) is an oscillating voltage in which a peak-to-peak voltage Vpp of 1600 V and a frequency f of 1800 Hz are superimposed on a DC voltage Vdc set to -500 V, while (b) is a fundamental frequency of 180.
The waveform has a pause time provided once every eight cycles of the AC component of 0 Hz, that is, a waveform that vibrates for seven cycles and then pauses for one cycle.

In the following, such a bias having a pause time will be referred to as a “blank bias”, and when it is vibrated for seven cycles as described above and then pauses for one cycle, it will be referred to as “blank ratio 7: 1”. (C) is a fundamental frequency of 1800 Hz
This is a waveform in which a pause time is provided once every six cycles of the AC component, that is, a blank bias of “blank ratio 5: 1”.

Here, if the blank bias is used as the developing bias, the fog generated due to the increase in the ratio of the high tribo regular toner when the number of prints increases can be suppressed. When a pause time is provided for the AC bias immediately afterward, the normally charged toner stays in the developing sleeve for a long time, and is developed on the photosensitive drum. This is because the amount can be drastically reduced.

Next, the control flow will be described with reference to the flowchart of FIG.

First, it is determined whether or not printing has started (step 71), and the storage means 3 built in the cartridge is determined.
From 0, the CPU reads the total print number data (step 72). Then, it is checked whether the total print number data is equal to or less than 6000 (step 73).
If the total number of prints data is less than 6000, the printing operation starts (step 75).

Next, each motor is driven (step 7).
6) A conventional developing bias is applied (step 7)
7).

Next, it is determined whether or not the printing operation has been completed (step 80). If the printing operation is to be continued, the process returns to step 75 to continue the printing operation and to accumulate and count the total number of prints.

If the printing is completed in step 80, the motors are stopped (step 81). As described above, the counted total print number data is written in the storage means 30 (step 82), and the processing is terminated.

If it is determined in step 73 that the total print number data is larger than 6000, it is checked whether it is 9000 or less (step 74), and the printing operation is started (step 75).

Next, each motor is driven (step 7).
6) If the total number of prints is 9000 or less, a developing bias of "blank ratio 7: 1" is applied (step 78). If the total number of prints is more than 9000, the development bias of "blank ratio 5: 1" is applied. A bias is applied (step 79).

Table 5 below shows the fog results when printing was performed up to 12,000 sheets at a resolution of 600 dpi and a process speed of 70 mm / sec, and when the number of prints was large and a blank bias was not used as the developing bias.

[0149]

[Table 5]

Table 6 below shows fog results when printing was performed up to 12000 at a resolution of 600 dpi and a process speed of 70 mm / sec, and when a large number of prints was used and a blank bias was used as a developing bias.

[0151]

[Table 6]

As described above, by detecting the number-of-prints data as needed during printing in the cartridge, it is grasped that the ratio of the high tribo regular toner increases as the number of prints increases. The toner ratio can be detected, and a blank bias is applied at the time of development during printing after a predetermined number of sheets. As a result, it is possible to prevent the occurrence of a fog image before the occurrence of a blank image, which occurs due to an increase in the ratio of high tribo regular toner when intermittent printing of a predetermined amount or more is continued.

Embodiment 8 Next, Embodiment 8 according to the present invention will be described with reference to the flowchart in FIG.

In this embodiment, the resolution is 600 dpi, the process speed is 70 mm / sec, and the resolution is 1200 dpi.
i. In an image forming apparatus that performs two-speed control at a process speed of 35 mm / sec, by changing the developing bias applied to the developing unit, the ratio of high tribo regular toner increases when the number of prints increases. This is characterized by preventing fogging images from occurring.

As described above, in the waveform of the developing bias shown in FIG. 19, (a) is a conventional developing bias waveform, (b),
(C) shows a developing bias waveform according to the present embodiment. (A) is a DC voltage Vdc set to -500V, 1
While the peak-to-peak voltage Vpp of 600 V is an oscillating voltage on which a frequency f of 1800 Hz is superimposed, (b) shows the “blank ratio 7:
1], after vibrating for 7 cycles, 1
The waveform has a pause for a period. (C) shows the “blank ratio of 5:
1 "blank bias.

In this embodiment, if the number of prints stored in the storage means of the cartridge is 2x + y <6000, a developing bias having no pause time is applied as in the past, and if 6000 ≦ 2x + y <12000, a blank is applied. A developing bias having a ratio of 7: 1 is applied, and 12000 ≦ 2x +
If y, a developing bias with a blank ratio of 5: 1 is applied. Here, x is the number of prints when the resolution is 600 dpi and the process speed is 70 mm / sec, and y is the resolution 1
This is the number of prints when 200 dpi and the process speed are 35 mm / sec.

In the flowchart of FIG. 20, first,
It is determined whether or not printing has been started (step 91), and the total number of prints data at each process speed is stored in the storage means 30 in the cartridge.
Is read (step 92). Then 2x + y ≦ 6
000 (step 93), 2x + y ≦
In the case of 6000, the printing operation starts (step 9).
5).

Next, each motor is driven (step 9).
6) A conventional developing bias is applied (step 9)
7).

Next, it is determined whether or not the printing operation has been completed (step 100). If the printing operation is to be continued, the process returns to step 95 to continue the printing operation and accumulate and count the total number of prints at each printing speed.

Conversely, when printing is completed, each motor is stopped (step 101). The total print number data at each print speed counted as described above is written in the storage means 30 (step 102), and the process ends.

In step 93, 6000 <2x +
In the case of y, it is checked whether 6000 <2x + y ≦ 12000 (step 94), and the printing operation is started (step 95).

Next, each motor is driven (step 9).
6) If 6000 <2x + y ≦ 12000, a developing bias of “blank ratio 7: 1” is applied (step 9).
8) When 12000 <2x + y, “blank ratio 5:
1] is applied (step 99).

Table 7 shows fog results when printing was performed at 12,000 sheets at a resolution of 600 dpi and a process speed of 70 mm / sec, and a blank bias was used as a developing bias when the number of prints was large.

[0164]

[Table 7]

Table 8 below shows fog results when printing was performed up to 12,000 sheets at a resolution of 1200 dpi and a process speed of 35 mm / sec, and a blank bias was used as a developing bias when the number of prints was large.

[0166]

[Table 8]

As described above, during printing in the cartridge, by detecting the number-of-prints data at each process speed as needed, it is possible to grasp the state where the ratio of high tribo regular toner increases as the number of prints increases. Therefore, the ratio of the high tribo regular toner can be detected, and a blank bias is applied at the time of development in printing after a predetermined number of sheets. In this way, it is possible to prevent the occurrence of a fog image before the occurrence of a blank image due to an increase in the ratio of high tribo regular toner when intermittent printing of a predetermined number or more is continued.

[0168]

As is apparent from the above description, according to the present invention, the density of a printed image in the initial state of use of the process cartridge or the developing device and the state of the printed image after being used for a while, and the density of characters and It is possible to prevent fluctuations in the line width constituting the figure, accurately detect the life of the electrophotographic photoreceptor, prevent fog images before white spots occur and fog images due to an increase in reversal toner, and improve the quality from the initial use state. It is possible to provide a process cartridge and a developing device capable of forming an image, and an image forming apparatus in which such a process cartridge or the developing device can be freely mounted.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a configuration diagram illustrating a process cartridge mounted on the image forming apparatus of FIG. 1;

FIG. 3 is a graph showing a relationship between a potential of an exposed portion of the photosensitive drum and a potential of a non-exposed portion.

FIG. 4 is a graph showing the relationship between the number of prints and the line width when the process speed is 70 mm / sec.

FIG. 5 is a graph showing the relationship between the number of prints and the line width when the process speed is 35 mm / sec.

FIG. 6 is a graph showing the relationship between the number of printed sheets and the line width when the process speed is 70 mm / sec in the image forming apparatus of the first embodiment.

FIG. 7 is a graph showing the relationship between the number of prints and the line width when the process speed is 35 mm / sec in the image forming apparatus according to the first embodiment.

FIG. 8 is a block diagram of the image forming apparatus according to the first embodiment.

FIG. 9 is a flowchart illustrating a control flow according to the first embodiment.

FIG. 10 is a configuration diagram illustrating a developing device according to a second embodiment.

FIG. 11 is a block diagram of an image forming apparatus according to a third embodiment of the present invention.

FIG. 12 is a flowchart illustrating a control flow according to the third embodiment.

FIG. 13 is a graph showing a relationship between an exposure amount of a photosensitive drum and an exposure portion potential.

FIG. 14 is a block diagram of an image forming apparatus according to a fourth embodiment.

FIG. 15 is a flowchart illustrating a control flow according to the fourth embodiment.

FIG. 16 is a flowchart illustrating a control flow according to the fifth embodiment.

FIG. 17 is a flowchart illustrating a control flow according to the sixth embodiment.

FIG. 18 is a flowchart illustrating a control flow according to the seventh embodiment.

FIG. 19 shows a developing bias obtained by superimposing a conventional developing bias and an AC voltage having a pause time used in Embodiment 6 of the present invention.

FIG. 20 is a flowchart illustrating a control flow according to the eighth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum (electrophotographic photosensitive body) 2 Charging roller (charging means) 3 Exposure device 4 Developing device 5 Toner (developer) 6 Developing blade (developer regulating means) 7 Developing roller (developer carrier) 18 Image forming apparatus Main body 20 Process cartridge 30 Storage means 100 High-pressure unit 181 CPU

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuko Ogama Canon Inc. 3- 30-2 Shimomaruko, Ota-ku, Tokyo

Claims (13)

[Claims] 1. An image forming apparatus having two or more process speeds, the process cartridge being detachably mountable to an image forming apparatus main body, an electrophotographic photosensitive member, a process means acting on the electrophotographic photosensitive member, and information relating to the process cartridge being reduced to a process speed. And a storage means for storing correspondingly. 2. The process cartridge according to claim 1, wherein the information stored in said storage means includes at least a use amount of the process cartridge at each process speed. 3. The image forming apparatus main body includes a high-voltage power supply for supplying power to the process unit, and the information stored in the storage unit includes at least a use amount of a process cartridge at each process speed. 2. The process cartridge according to claim 1, wherein an image forming condition at the time of printing at a certain process speed is corrected in accordance with the usage amount of the process cartridge at the process speed. 4. The image forming apparatus main body includes a high-voltage power supply for supplying power to the process unit, and the information stored in the storage unit includes at least a use amount of a process cartridge at each process speed. 2. The process cartridge according to claim 1, wherein when the used amount of the process cartridge at the process speed is equal to or less than a predetermined amount, the correction is performed in a direction to promote the image forming condition at the time of printing at a certain process speed. 5. The image forming apparatus main body includes a high-voltage power supply for supplying power to the processing unit, and the information stored in the storage unit includes at least a usage amount of a process cartridge at each processing speed. 2. The process cartridge according to claim 1, wherein when the used amount of the process cartridge at the process speed is equal to or more than a predetermined amount, a signal indicating a replacement time of the process cartridge is sent to the image forming apparatus main body or the computer. 6. A process cartridge detachably mountable to an image forming apparatus main body, an electrophotographic photoreceptor, a process unit acting on the electrophotographic photoreceptor, and a storage unit for storing information on the process cartridge corresponding to a process speed. The image forming apparatus main body has a developing bias applying unit that applies an oscillating voltage obtained by superimposing an AC voltage on a DC voltage to a developing unit included in the process unit, and information stored in the storage unit. Contains at least the usage amount of the process cartridge, and when the usage amount of the process cartridge is equal to or more than a predetermined amount, the alternating voltage of the oscillating voltage has a predetermined pause time after a voltage oscillation for a predetermined time, which periodically The cycle for setting the pause time is variable according to the total usage of the process cartridge. A process cartridge that corrects the image forming condition in a direction that promotes the image forming condition. 7. The process cartridge, wherein a charging unit as the process unit, a developing unit or a cleaning unit, and the electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge is attached to the image forming apparatus main body. 7. The process cartridge according to claim 1, wherein the process cartridge is detachable. 8. The process cartridge, wherein at least one of a charging unit, a developing unit, and a cleaning unit as the process unit and the electrophotographic photoreceptor are integrally formed into a cartridge, and the cartridge is attached to an image forming apparatus main body. The process cartridge according to claim 1, wherein the process cartridge is detachable. 9. The process cartridge is a cartridge in which at least the developing means as the process means and the electrophotographic photosensitive member are integrally formed as a cartridge, and this cartridge is detachably mountable to an image forming apparatus main body. The process cartridge according to any one of claims 1 to 6. 10. An image forming apparatus for detachably attaching a process cartridge and forming an image on a recording medium, comprising: (a) an electrophotographic photosensitive member, a process unit acting on the electrophotographic photosensitive member, and a process cartridge. Mounting means for detachably mounting a process cartridge having storage means for storing information corresponding to the process speed in the apparatus main body; and (b) transport means for transporting the recording medium. Characteristic image forming apparatus. 11. An image forming apparatus for detachably attaching a process cartridge and forming an image on a recording medium, comprising: (a) an electrophotographic photosensitive member, process means acting on the electrophotographic photosensitive member, and a process cartridge. Storage means for storing information in accordance with a process speed, wherein the image forming apparatus main body has a developing bias applying means for applying an oscillating voltage obtained by superimposing an AC voltage on a DC voltage to a developing means included in the process means. When the information stored in the storage means includes at least the usage amount of the process cartridge, and the usage amount of the process cartridge is equal to or more than a predetermined amount, the AC voltage of the oscillation voltage is changed to a predetermined value after voltage oscillation for a predetermined time. Has a downtime that repeats periodically and depends on the total usage of the process cartridges. Mounting means for removably mounting a process cartridge for setting a pause period to be variable and correcting the image forming conditions in a direction to promote the image forming condition, to the apparatus main body; and (b) conveying the recording medium. And an image forming apparatus. 12. A developing device having a developing unit provided with a developing container and detachable from the image forming apparatus main body, further comprising a storage unit for storing information on the developing device in correspondence with a process speed. Developing device. 13. A developing device having a developing unit provided with a developing container and detachable from an image forming apparatus main body, further comprising a storage unit for storing information on the developing device in correspondence with a process speed, The apparatus main body has a developing bias applying unit that applies an oscillating voltage obtained by superimposing an AC voltage on a DC voltage to the developing unit, and the information stored in the storage unit includes at least a usage amount of the developing device, When the amount is equal to or more than a predetermined amount, the AC voltage of the oscillating voltage is
After the voltage oscillation for a predetermined time, the apparatus has a predetermined pause time, which is repeated periodically, and the cycle for setting the pause time is variable according to the total use amount of the developing device to promote image forming conditions. A developing device that corrects the developing direction.